St. Cloud began July with a 96°F high, which would have
been the hottest temperature of the previous three years, but we
did have a 101°F high on June 7, still the hottest temperature
of the summer. However, the key heat was during July 16-20. St. Cloud had
4 straight days with a high
of at least 90°Fduring this time, both
the first and the longest St. Cloud heat wave (three consecutive days with
a high of at least 90°F) since September 3-6, 2007. Recently, however,
St. Cloud did have a 9-day heat wave on July 23-31, 2006, topped off with
the previous 100°F high before this June on the 31st. The record heat
wave in St. Cloud was set on
July 5-18, 1936, with 14 consecutive highs of at least 90 degrees.

There were a total of 8 July days with a high
of at least 90°F, nearly double the average number of 4.7
and the most since July 2006 when there were 15 days with such warm highs.
So far in the summer of 2011, St. Cloud has had 11 days with a a high of
at least 90°F, which is the normal amount for the entire summer. In
St. Cloud's recent past, the summer of 2006 had 20 days with a 90-degree
high and the extremely hot summer of 1986 had 33 days, the third
highest total in St. Cloud records.

Record Moisture in Parts of Minnesota

However, what made this July's heat more difficult to overcome
was the high humidity throughout. The Minneapolis-St.
Paul International Airport set a record with an 82°F dew
point on July 19. Statewide, the amount of moisture was incredible with
several long-term cooperative stations setting dew point records.
The dew point was actually higher in Moorhead, hitting a greenhouse like
88°F, which combined with a 93°F temperature to produce an incredible
heat
index of 130°F. That dew point, however, didn't agree with
other area dew points. Local sources, such as a very heavy rainfall earlier
in the morning and having the sensor close to soybean and corn crops, which
put out moisture due to the food-making process. However, oppressive dew
points ruled several times through that period, producing heat indices as
high as 117°F in St. Cloud on July 19.

Dew point is the best measure of moisture in the air, since
it only changes as the amount of moisture changes. Relative humidity cannot
directly determine the amount of water vapor in the air since it changes
with both moisture and temperature. So, the relative humidity during a blizzard
(near 100%) can be higher than our most humid day (our worst heat index
was produced
by a temperature of 94°F and a dew point of 82°F, which
produces a relative humidity of only 68%, even though there was nearly 16
times more moisture in the air in the July heat wave).

Historic Streak of Warm Lows

Unfortunately, St. Cloud does not have an extensive history
of dew point readings because the station did not report between 9 PM and
5 AM when the observation required a human to read it. As a proxy for high
dew point events, I have researched the history of low temperatures exceeding
70°F in St. Cloud. During July 16-20 of this year, St. Cloud had 5 straight
days with a low
of at least 70°F. There have been only 21
streaks of at least 3 straight days since St. Cloud temperature
records began in 1893. That tied for the third
longest streak of such warm lows with June 1931 and July-Aug.
1955. Once again, the longest streak happened during the July 1936 heat
wave with 8 straight lows of at least 70 degrees. In total, there have been
6 July days with a low of at least 70 degrees, the
most since July 1941. For the summer so far, St. Cloud has had
7 lows of 70 or higher, which ties 2005.

Even though there were only two more 90-degree highs and no
more 70 degree lows after July 20, St. Cloud did not have a high below 80
degrees for the final 17 days of July and only two lows below 60 degrees
in the last 18 days of the month. Still, this was only a small taste of
the heat and humidity that has stayed in the Southern Plains during most
of the summer. For example, Oklahoma
City has had 38 days with a high of at least 100 and two straight
months (61 days) with a high of at least 90 degrees.

Overall, the average July low in St. Cloud was 64.0°F.
That's the 6th warmest average July low out of 115 years. The only 5 years
that had a warmer July low were 1936 and earlier. On the other hand, the
average high temperature of 86.2°F ranked only tied for 14th warmest.
There were hottest high July temperatures in 1974, 1975, 1988, and 2006
within the past 40 years. The
last 17 days of this July had highs of at least 80 degrees, but
that came on the heels of a record
cold high on July 14. Thanks to persistent clouds from thunderstorms,
the high was only 68°F.

You Want a Hotter July? Ask Grandma

July of 1936 in St. Cloud was the
hottest month in St. Cloud records with an average temperature
of 78.9°F more than a degree higher than the second place July. That
was nearly four degrees hotter than this July. Included in July 1936 was
arguably the worst
heat wave in St. Cloud records. Between July
5-18, there were 14 straight days with a high of at least 90
degrees. Nine
of those highs, none cooler than 98 degrees, still stand as record
highs. That includes the 107°F high on July 13, 1936, tied with two
other days for St. Cloud's hottest temperature on record.

While St. Cloud more frequently got into the very warm and
humid air during July, we spent most of the month near the border between
the edge of the searing air mass to the south and slightly cooler air to
the north. That put the Dakotas, Minnesota, Nebraska, Wisconsin, and Iowa
frequently in the path of large thunderstorm complexes. There was a total
of 5.63 inches of rain in July at the St. Cloud Airport, more than two inches
over the 1981-2010 average July rainfall of 3.31 inches. That made July
2011 the 12th wettest July on record, just a quarter inch short of cracking
the
10 wettest Julys. It was the wettest July in St. Cloud since
1997 when 6.89 inches fell.

Since the growing season began on April 1, the St. Cloud Airport
has picked up 16.16 inches of rain, 3 inches more than normal. However,
given the localized nature of the heavy rainfall, some areas nearby have
picked up far more. (St. Cloud managed to dode the thunderstorms for most
of the last two weeks of the month, picking up "only" 1.05 inch.
Nearly all of central Minnesota has at
least 25% more rainfall than average with southeastern Stearns
County, northern Wright and Meeker Counties in the wettest 5% of growing
seasons so far. Becker, in particular, has been more than 4
inches above average during the past 4 weeks and 7.31 inches
above normal for the growing season.

The summer of 2011 has not had the record number of Minnesota
tornadoes that
last summer produced, including the 45
tornadoes, 4 of them being EF-4, on June 17. However, July 2011
had several days with prolific severe weather, mostly dominated by strong
straight-line winds and flooding rainfall.

July 1 - Waite Park Tornado and Derecho in N. St.
Cloud and east

St. Cloud and Waite Park were hard hit by the combination of a weak tornado
and a long-lived straight line wind damage event. The tornado which was
on the ground from the I-94/Hwy. 23 interchange to Division Street west
of the Parkwood 18 Theater, ended up being
rated EF-0 (got to do some scrolling from there) with top winds
estimated at 65 MPH. The north side of St. Cloud into Sauk Rapids and northern
Benton County had widespread straight line wind damage with winds estimated
at 65-70 MPH. This was one of several tree downings associated with the
derecho described below.

The thunderstorms took the form of
a pair of lines of thunderstorms that moved from central South
Dakota across central and southern Minnesota. The northern one, that took
on the shape of a comma, became a "bow echo," a typical radar signature
for a line of storms producing widespread wind damage. Damaging winds were
reported as high as 80 MPH in Marshall, 78 MPH in Redwood Falls,
and 71
MPH in the Big Lake area. A lot of damage has been reported in
Redwood Falls, Sacred Heart, Danube, and many other locations, but the general
path of wind damage was in two large lines. The northern one
from eastern South Dakota through central Minnesota to the Ashland, Wisconsin,
area was long enough to be considered a derecho,
a long-lived line of straight line wind damage. Other long-lived straight
line. Heavy rain, as much as 2.75 inches in 2 hours in Sartell, and large
hail were
also reported (baseball sized near Dassel and Monticello, one
stone 4 1/4 inches in diameter (softball-sized). There have been no confirmed
tornado touchdowns, since this type of storm tends to produce mostly straight-line
wind damage.

Other longer-lived examples of straight-line wind damage in Minnesota
include the July 4, 1999 storm that cut a swath of wind damage
from Fargo through the Boundary Waters and a July 1, 1997 that produced
wind damage from central Minnesota to Michigan, including major damage in
Big Lake and $10 million damage in Monticello.

The St. Cloud Airport picked up 1.00 inch of rain and wind gusts up to
54 MPH. The temperature also plunged from 88 degrees just in advance of
the storm to 68 degrees in 36 minutes between 5:27 and 6:03 PM. At SCSU,
there was 1.44 inches of rain. There were 2.83 inches of rain on the west
side of St. Cloud, leading to flooding.

Sauk Centre
had winds estimated of up to 90 MPH with about 200 trees knocked over.
There was scattered wind damage in a path from Ortonville through Columbia
Heights and Forest Lake, although the swath of damage wasn't as wide or
as consistent as in the July 1 storm. One small tornado was found along
the Kandiyohi-Meeker county line. It was only on the ground for about 20
seconds.

July 19 - Straight Line Wind Damage On the Edge of
Record Dew Points In Milaca, Foreston, Ronneby

In St. Cloud proper, the storms left a gap right over the city, so only
a trace of rain fell at the Airport and nothing at SCSU, marking a continuation
of the Thursday through Saturday weather which saw storms all around us,
but little more than a sprinkle hitting us. The
St. Cloud deflector lives!

Effect on Area Agriculture

The heavy rain has continued to slow the agricultural progress,
although the heat at times in July helped growers. The latest Minnesota
Crop Weather Report shows
only 22% of the topsoil with surplus moisture. That's down considerably
from the 50%
seen on June 27. Basically, the heat of the second half of the
month allowed many crops to catch up for earlier time, if the fields hadn't
been damaged by earlier flooding. Corn silking is now up to 83%, just short
of the 85% average. There are many puddles still standing on farm fields.

August Starting Off Hot and Drenchy

Persistent thunderstorms have caused a bunch of problems with
flash flooding and wind damage on August 1 with storms producing a wind
gust of 63 MPH on August 2. Then the weather will calm down and dry out
for the bulk of this week. Still, it's hard to go more than 3 days in this
pattern without a decent chance of thunderstorms.

Still, the searing heat in the southern Plains will likely
continue for much of this month, barring the landfall of a hurricane on
the Texas or Mexico coast.

New 30-Year Normals Announced

July 2011 also marked the release of the new 30-year averages,
encompassing the years 1981-2010. The result is that the decade of the 1970's
were dropped and the decade of the 2000's were added to produced the new
normals. The new averages show a large increase in temperatures with the
biggest gains in our part of the country, especially for
low temperatures and cool
season temperatures. This is due, in large part, to the very
warm cold season temperatures of the late
1990's and early 2000's, while very cold winters like 1977-78
and 1978-79 dropped out of the averages.

While data from a single station cannot be considered proof
of global warming, it is consistent with the globally
observed temperature trend, featuring a sharp rise from the late
1970's to the early 2000's. This warming is larger than the accepted 20th
century warming during 1900-1940.

The
St. Cloud averages actually show increases in average temperature
in every month but May with the biggest increases in the winter months.
That is consistent with the computer forecasts of global warming; warming
will be largest during the cold season and near the poles. There has
also been an increase of precipitation by about half an inch,
most notably in the spring and fall. This is also consistent with the forecasts
of increased precipitation at high latitudes in a globally warmed atmosphere.
However, the
snowfall did fall, especially in January, but during all winter
months in general.